Many bacteria possess a large number of chemoreceptors that recognize a variety of different compounds. More than 60% of the genomes analyzed in this study contain paralogous chemoreceptors, suggesting that they emerge with high frequency. We provide first insight on how paralogous receptors have evolved and show that two chemoreceptors with a narrow ligand range have evolved from an ancestral protein with a broad chemoeffector spectrum. Protein structures show that multiple changes in the ligand-binding site account for the differences in the ligand spectrum. This work lays the ground for further studies aimed at establishing whether the principles of ligand-binding evolution reported here can be generalized for a wider spectrum of sensory proteins in bacteria. Pseudomonas aeruginosa PAO1 is an important model to study their function. Of the 26 chemoreceptors of this strain, PctA has a broad ligand range and responds to most of the proteinogenic amino acids, whereas PctB and PctC have a much narrower range and show strong ligand preference for l-glutamine and γ-aminobutyrate, respectively. Using several comparative genomics approaches, we show that these receptors are paralogs: pctA gene duplication in the common ancestor of the genus Pseudomonas led to pctC, whereas pctB originated through another, independent pctA duplication in the common ancestor of P. aeruginosa. Thus, the broad-range amino acid chemoreceptor was evolutionarily older, and chemoreceptors that complemented “missing” amino acid sensing abilities arose later in specific Pseudomonas lineages. Using comparative sequence analysis, newly solved crystal structures of PctA, PctB, and PctC ligand-binding domains, and their molecular dynamics simulations, we identified a conserved amino acid recognition motif and changes in the ligand-binding pocket that led to novel ligand specificities. In addition, we determined major forces driving the evolution of this group of chemoreceptors.Chemoreceptor-based signaling pathways are among the major modes of bacterial signal transduction, and  Bacteria need to constantly adapt to changing environmental conditions to ensure survival. Among the different adaptational strategies is the ability of many bacteria to perform chemotaxis, a behavior based on the action of chemosensory pathways , 2. TypiPseudomonas aeruginosa PAO1 as a model. This strain has 26 chemoreceptors, and approximately half of them have been functionally characterized domains, and the light gray segments show the different types of the MCP (methyl-accepting chemotaxis protein) signaling domains. The effectors for characterized chemoreceptors as well as their binding mode are indicated. Download FIG S1, PDF file, 0.3 MB.Schematic representation of Copyright © 2020 Gavira et al.2020Gavira et al.Creative Commons Attribution 4.0 International license.This content is distributed under the terms of the P. aeruginosa PAO1 is strongly attracted to all 20 l-amino acids  Organization and environment of the pctA, pctB, and pctC genes according to the Pseudomonas database (http://www.pseudomonas.com). (B) Sequence alignment. The transmembrane regions are shaded in yellow and flank the ligand-binding domains. Download FIG S2, PDF file, 0.4 MB.The chemoreceptors PctA, PctB, and PctC of Copyright © 2020 Gavira et al.2020Gavira et al.Creative Commons Attribution 4.0 International license.This content is distributed under the terms of the We report here the evolutionary history of Pct paralogs and report the three-dimensional (3D) structures of the LBDs from PctA, PctB, and PctC chemoreceptors in complex with different chemoattractants.Pseudomonadaceae, while PctC is present only in the genus Pseudomonas  Genetic alterations of the pctA, pctB, and pctC genes and in their neighborhoods in P. aeruginosa strains. (C) Presence of pctA, pctB, and pctC genes in different P. aeruginosa complete and draft genomes. (D) Abundance of PctA homologs in different bacterial strains. Download Data Set S1, XLSX file, 0.1 MB.Bioinformatics data. (A) Presence of PctA homologs in different Copyright © 2020 Gavira et al.2020Gavira et al.Creative Commons Attribution 4.0 International license.This content is distributed under the terms of the P. aeruginosa genomes. This analysis revealed many changes in the neighborhoods of these genes, ranging from changing positions within the neighborhood to duplications, conversions to pseudogenes, and gene loss  in Pseudomonas putida GB-1; the closest homolog of TlpQ is KFX69128.1 (66%) in Pseudomonas taeanensis MS-3. Download FIG S3, PDF file, 0.2 MB.Clusters of PctA homolog sequences paired with corresponding sequence logos of ligand-binding pocket regions. Regions of sequence logos with alterations in the binding motif are highlighted in turquoise. I, Copyright © 2020 Gavira et al.2020Gavira et al.Creative Commons Attribution 4.0 International license.This content is distributed under the terms of the Pseudomonadaceae  Ribbon diagrams of the crystallographic dimers present in the asymmetric units of PctA-LBD and PctC-LBD. Chains A and C are shown for PctC-LBD. Bound ligands are shown in purple. (B) Topological organization of secondary structural elements of the three paralogous structures. Download Copyright © 2020 Gavira et al.2020Gavira et al.Creative Commons Attribution 4.0 International license.This content is distributed under the terms of the PctC-LBD crystallized in a different space group with 7 chains in the asymmetric unit, of which only 2 contained GABA inside the binding pocket of the membrane-distal module. The overall structures of the three paralogous proteins are similar , and the10.1128/mBio.03066-19.7TABLE S1Table S1, PDF file, 0.2 MB.Structural alignment of PctA/B/C-LBD structures. (A) Alignment of structures among each other. (B) Alignment with homologous structures deposited in the PDB data bank. (C) Relative positions of the four amino acids conserved in the ligand-binding pocket of the three paralogs. Download Copyright © 2020 Gavira et al.2020Gavira et al.Creative Commons Attribution 4.0 International license.This content is distributed under the terms of the Vibrio cholerae, which also bind amino acids (We have conducted molecular dynamics (MD) simulations to measure the extension of the different binding pockets. Data show that the binding sites are within the margin of error of very similar size . On the no acids .10.1128/mBio.03066-19.1TEXT S1Text S1, PDF file, 0.4 MB.Study of the size of the ligand-binding pocket and ligand orientation in PctA/PctB/PctC-LBD structures based on MD simulations. Download Copyright © 2020 Gavira et al.2020Gavira et al.Creative Commons Attribution 4.0 International license.This content is distributed under the terms of the Ligand-induced structural changes have been observed for four-helix bundle domains , 32, butThe inspection of electron densities in the different binding pockets has permitted the placement of the different amino acids , and the10.1128/mBio.03066-19.6FIG S5FIG S5, PDF file, 0.3 MB.Amino acids present in the ligand-binding sites of the three paralogous receptors. Mesh representation of the final |2Fo–Fc| electron density map contoured at 1.0-σ level. Amino acid structures are shown in stick mode. Download Copyright © 2020 Gavira et al.2020Gavira et al.Creative Commons Attribution 4.0 International license.This content is distributed under the terms of the The inspection of all structures showed that amino acids from 22 different homologous positions interact with the bound ligand, and in the case of PctA, 19 amino acids interact with bound amino acids. The side chains of the bound amino acids form hydrophobic interactions with Phe99 and Tyr101 (β1) and with different residues on the segment 109 to 118, which corresponds to the C-terminal part of β2 and the following loop ; Fig. S4l-Gln (DK [equilibrium constant] = 1.2 μM) but also binds l-Arg with an affinity of 64 μM  scores  scores  (Table S) scores  range fr10.1128/mBio.03066-19.8TABLE S2Table S2, PDF file, 0.3 MB.Glide XP docking scores obtained for PctA-LBD, PctB-LBD, and PctC-LBD for the best ligand candidates. Download Copyright © 2020 Gavira et al.2020Gavira et al.Creative Commons Attribution 4.0 International license.This content is distributed under the terms of the Subsequently, the collection of all natural compounds  from the ZINC database was used for docking experiments with the membrane-proximal module. For all compounds, the absolute value of the docking scores was much lower than those of the ligands that bind to the membrane-distal module . Top docEscherichia coli laboratory strain K-12 has five chemoreceptors—Tsr, Tar, Trg, Tap, and Aer  and at the level of individual amino acids, specifically in sensory domains. Comparative genome analysis revealed that gene duplication is a major driving force in the evolution of this chemoreceptor family: more than 60% of genomes analyzed in this study contained paralogous chemoreceptors of this type. Many paralogs originated from multiple independent gene duplication events. Possible fates for duplicated genes include neofunctionalization, subfunctionalization, or loss. We observed a substantial number of pseudogenes and a complete loss of pctA, pctB, and pctC genes (in various combinations) in several strains indicating “unsuccessful” evolutionary “experiments.” On the other hand, the birth of PctC in the common ancestor of the genus Pseudomonas and the birth of PctB in the common ancestor of Pseudomonas aeruginosa are examples of “successful” gene duplications. All “successful” duplication events resulted in very specific subfunctionalization of paralogs—substantial changes in the chemoreceptor sensory domain leading to changes in the ligand repertoire.The number of chemoreceptors in different bacteria varies depending on the environment they inhabit . Even witransfer . The numP. aeruginosa and the fact that only a few amino acid residues in the signaling domain determine the pathway specificity  that showed bound chemoeffector (lactate) in the membrane-proximal module . A recent study revealed that a ΔpctABC triple mutant had a significant reduction in chemotaxis and immobilization along wounds of human CF airway epithelial cells . Taxonomy information for phylogenetic profiling was retrieved from the Genome Taxonomy Database . Gene neighborhoods were identified using the MiST 3.0 database  run BLAST all-versus-all; (ii) collect best high-scoring pairs for each hit; (iii) collect best hits for each genome; (iv) reduce redundancy by clustering genomes if (a) the number of PctA, PctB, and PctC homologs is the same, (b) a query coverage of each blast hit equals 100%, and (c) sequence identity for all PctA, PctB, and PctC homologs for a given pair is 100%; and (v) from each cluster, pick representative sequences from a genome with the highest level of assembly. The resulting representative data set contained 2,143 sequences from the final set of genomes. Sequences were then aligned, and a maximum likelihood tree was built from this alignment. In order to reveal sequence conservation patterns within the dCache_1 domain, branches on the tree were compressed into clusters and sequence logos were generated based on the multiple sequence alignment of the dCache_1 regions within each cluster. A genome tree for phylogenetic profiling was prepared using the Genome Taxonomy Database  glycerol to the mother liquid followed by an overnight equilibration of the crystal-containing capillaries. The best-diffracting crystals were used to collect X-ray data diffraction at beamlines Promixa-I of SOLEIL , XALOC of ALBA , and ID23-1, ID23-2, ID29, and Bm14U of ESRF  synchrotron sources. Data were indexed and integrated with XDS . The resulting proteins as well as the apo form were used for initial crystallization screening at 293 and 277 K, using the counterdiffusion technique , 0.1-mm-with XDS , and thewith XDS  of the Cwith XDS .10.1128/mBio.03066-19.9TABLE S3Table S3, PDF file, 0.1 MB.Conditions used for protein crystallization. Download Copyright © 2020 Gavira et al.2020Gavira et al.Creative Commons Attribution 4.0 International license.This content is distributed under the terms of the Vibrio cholerae  were used as a search model for the molecular replacement of PctA-LBD-Ile X-ray data using Phaser (l-Trp and l-Met but using the refined PctA-LBD as the search model. PctB-LBD-Arg and PctC-LBD-GABA were also solved using PctA-LBD as the initial search model, but in the case of PctC-LBD-GABA, a solution was found only when the anomalous contribution was included and used within the Rickshaw pipeline (Coordinates from the LBD of an uncharacterized chemoreceptor of g Phaser . Refinemg Phaser  of the Pg Phaser  followedg Phaser . Consecug Phaser  and MolPg Phaser . A similpipeline . Table 1pipeline , and grapipeline . Structupipeline .profix program from the JACKAL package (a calculated with PROPKA software (All protein-ligand complexes were subjected to structural refinement with the  package . The hydsoftware  using Chsoftware . To avoisoftware  for 20,0software  using stThe atomic structures of PctA-LBD, PctB-LBD, and PctC-LBD were refined and optimized with the Protein Preparation Wizard of the Schrödinger suite . The cool-Ile, 5T65; l-Trp, 5T7M; l-Met, 5LTX; l-Gln, 5LTO; l-Arg, 5LT9; GABA, 5LTV.The coordinates and the experimental structure factors have been deposited in the Protein Data Bank with the following identifiers:


The electrical conductivity enhancement in the formamide-treatment process was in part ascribed to the removal of the insulating PSS component. Further treatment of PEDOT:PSS film with ionic liquid caused dedoping of PEDOT and hence increased in Seebeck coefficient. In contrast, second series post-treatment method led to the reduction in electrical conductivity from 2,873 to 641 S/cm but a big improvement in the Seebeck coefficient from 14.9 to 61.1 μV/K and thus the overall power factor reached up to ~239.2 μW/K2m. Apart from the improvement in electrical conductivity, the increase in Seebeck coefficient is on account of the substantial dedoping of PEDOT polymer to its neutral form and thus leads to the big improvement of its Seebeck coefficient. The environmental stability of ionic liquid-treated PEDOT:PSS films were examined. It was found that the ionic liquid treated PEDOT:PSS retained more than 70% Seebeck coefficient and electrical conductivity at 75% RH humidity and 70°C for 480 h. The improved long-term TE stability is attributed to the strong ionic interaction between sulfonate anions and bulky imidazolium cations that effectively block the penetration of water and lessen the tendency to take up water from the air.Poly:poly(styrenesulfonate) (PEDOT:PSS) is one of the most popular conducting polymers and widely used as polymer thermoelectric materials, and its thermoelectric performance could be improved by a variety of post-treatment processes. This paper reported two series of post-treatment methods to enhance the thermoelectric performance. The first series method included pre-treatment of PEDOT:PSS film with formamide, followed by imidazolium-based ionic liquids. The second series method included pre-treatment of PEDOT:PSS film with formamide, followed by sodium formaldehyde sulfoxylate, and finally imidazolium-based ionic liquids. Two series of post-treatment methods significantly improved the power factor of PEDOT:PSS when compared to that of PEDOT:PSS treated with formamide only. For example, using the first series post-treatment method with 40 vol.% ionic liquid 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl) amide, the Seebeck coefficient of the PEDOT:PSS film increased from 14.9 to 28.5 μV/K although the electrical conductivity reduced from 2,873 to 1,701 S/cm, resulting in a substantial improvement in the overall power factor from 63.6 to 137.8 μW/K TE devi0.5 Ren,  with ZT 2)-doped PAc, has a power factor (PF = S2σ) of ~ 1,350 μW/K2m, but it has no practical application due to its poor stability and processability  have immerged as promising TE materials due to the tunable σ, low κ, and relatively low production cost. The commonly studied CPs include polyaniline (PANi)  treatment. The effect of anions associated with ILs on the TE properties of treated PEDOT:PSS films were also investigated, revealing that the type of anions played a somewhat role in affecting the TE properties. PEDOT:PSS films treated with 40 vol.% IL, 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl) amide (BMIM-TFSI), achieved a highest PF of 239.2 μW/K2m, and it also demonstrated a very good environmental stability, indicating that our approach is potential for practical TE application in the future.In this work, we reported the enhancement of the PEDOT:PSS solution  was purchased from Heraeus. Formamide, sodium formaldehyde sulfoxylate (SFS), 1-butyl-3-methylimidazolium tetrafluoroborate (BMIM-BF4), 1-butyl-3-methylimidazolium trifluoromethanesulfonate (BMIM-OTf) or 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl) amide (BMIM-TFSI) were purchased from Sigma-Aldrich. All chemicals were used as received without further purification. The chemical structures of ionic liquids are shown in PEDOT:PSS solution was filtered using a 0.45 μm poly (vinylene difluoride) PVDF syringe filter. The glass substrates were cleaned with deionized (DI) water, detergent, acetone, and isopropanol in an ultrasonic bath consecutively and dried with nitrogen gas. The glass substrate was subjected to ultraviolet (UV)-ozone surface treatment for 15 min before use.2O solvent and then kept at 80°C for another 10 min to further remove the residual solvent. Finally, the PEDOT:PSS films were annealed at 130°C for 10 min to ensure complete evaporation of the solvent. The final thickness of each dried PEDOT:PSS film was in the range of 8–10 μm.PEDOT:PSS films were prepared by drop-casting a 300 μL of PEDOT:PSS solution on the pre-cleaned glass substrate using a micropipette. The deposited sample was firstly dried in air at 50°C for 30 min to mainly drive off the HFor the post-treatment process, 140 μL formamide was first dropped onto the PEDOT:PSS films on a hot plate at 180°C and then the films were dried for about 10 min to remove the residual formamide. Afterward, the formamide treated PEDOT:PSS films were cooled to room temperature in air, and these films were rinsed with DI water and then dried again on a hot plate at 140°C for 5 min. The detailed procedures for treatment can be found in our previous work  with concentrations of i.e., 0, 20, 40, 60, 80, and 100 vol.% ILs in methanol were prepared. Then pre-treated PEDOT:PSS films with formamide and SFS were further treated with ILs in methanol according to the following steps: 150 μl IL in methanol was dropped onto PEDOT:PSS film at room temperature and left for 30 min. Next, the samples were dried by the aid of blowing N2 gas at a pressure of 0.15 MPa for another 30 min to remove the residual solvent of IL. Then the films were rinsed by dipping the films in DI water for three times and then finally annealed at an elevated temperature of 140°C under air to remove the residual solvent. These treated samples were cooled down to room temperature before TE property measurements. All treatments were conducted at their optimized treatment temperatures and conditions. The post-treatment with ILs was conducted at room temperature. Initially, three ILs (ILs)  of the films was determined by the four-point probe method  at the room temperature. The Loresta-GP MCP-T610 meter includes standard accessories PSP probe ] and probe checker [RMH112 (MCP-TP06P)]. The edges of the film were located at 10 mm from the measurement point. The σ is the inverse of the resistivity ρH, which is calculated in terms of the equation: ρH = RSt where Rs and t are resistance and thickness of the film, respectively . The sheet resistance  of 55% (V). Simultaneously, K-type thermocouples were connected to a data logger (Omron ZR-RX45) to collect the actual temperatures of the PEDOT:PSS film. The voltage probes and thermocouples were placed at the same temperature zone on each side so that the measured voltage corresponded to the actual thermal gradient between the two voltage probes. The measured thermovoltage was corrected by the thermovoltage of Au wire to obtain the absolute S of the films. S was estimated based on the slope of the linear relationship between thermoelectric voltage and the temperature difference of the two probes . The Hall coefficient RH was measured using a Hall-effect measurement system (Ecopia HMS-5000) with the van der Pauw method. First, the Ag electrodes were deposited onto the film through a shadow mask. The carrier concentration n and mobility μ were calculated using the following equations: n = 1/ (|RH|× e) and μ = |RH|/ρH, where e is electron charge. The κ was calculated using the equation κ = b2/Cpρm, where ρm, b, Cp are density, thermal effusivity, and specific heat capacity, respectively. The b was measured with a Pulsed Light Heating Nano TR (NETZSCH) system with an ultrafast pulsed laser flash method using the front heating-front detection mode, which is designed for the thermal analysis of 30 nm −20 μm thin films. The Cp was measured independently by differential scanning calorimeter (DSC) (Mettlier Toledo DSC1). The ρm at room temperature was calculated from the mass and volume of the film. For all measurements, at least 10 samples for each measurement were prepared at the same conditions, and measurements were carried out at least five times for each sample to obtain the statistical results. X-ray diffraction (XRD) patterns of the films were obtained by a D8 Advance System (Bruker Corporation) equipped with a Cu Kα X-ray source, λ = 0.15406 nm. The Raman spectroscopy measurements were conducted on a Raman microscope (Renishaw) with a laser wavelength of 785.5 nm, a laser beam spot size of 200 μm and an accumulation time of 30 s. The absorption spectra measurement was performed on a UV-Vis-NIR spectrophotometer . The films were spin-coated on quartz substrates. X-ray photoelectron spectroscopy (XPS) of the films were obtained by the Theta Probe Angle-Resolved X-ray Photoelectron Spectrometer (ARXPS) System (Thermo Scientific) using monochromated, micro-focused Al Kα X-ray photons (hυ = 1486.6 eV) at a base pressure of 1 × 10−9 Torr and a step size of 0.1 eV. The curve fitting was carried out using the Avantage software. Atomic force microscopy (AFM) images were taken on a Bruker Dimension Icon AFM using the tapping mode. Ultraviolet photoelectron spectroscopy (UPS) measurement of the films was obtained by using the He I photon (21.22 eV) radiation line from a discharge lamp, with an experimental resolution of 0.15 eV. All UPS measurements of the onset of photoemission for determining the Φ were performed using standard procedures with a −4.5 V bias applied to the sample. The films were prepared by drop-casting a PEDOT:PSS solution onto a pre-cleaned silicon substrate.The ) of 55% . It consPEDOT:PSS films were placed in a humidity controlled chamber and their TE performance was measured at varied temperature and humidity conditions in order to study the effect of humidity on TE properties of PEDOT:PSS films  or 1-butyl-3-methylimidazolium trifluoromethanesulfonate (BMIM-OTf) in methanol were used for this study. ILs are composed of positively and negatively charged species . In these three ILs, the cation is always BMIM, and only the anion is different. All post-treatment methods are summarized in Three different ILs, 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl) amide (BMIM-TFSI), 1-butyl-3-methylimidazolium tetrafluoroborate . Introduction of IL treatment reduced the σ, while noticeably improved the S of IL-F-PEDOT:PSS films. It is worth noting that the σ and S of IL-F-PEDOT:PSS films almost remain unchanged when the concentration of ILs increases from 20 to 80%, suggesting that they are less affected by the concentration of the ILs. Treatment with 20–100 vol.% BMIM-TFSI  led to an enhancement of the S from ~14.9 to ~28.1 μV/K and a significant reduction in the σ from ~2,873 to ~1,678 S/cm. Overall, in comparison to the PF of around 65 μW/K2m without IL treatment, the optimal PF reaches 137.8 μW/K2m when 40 vol.% BMIM-TFSI solution is used. Interestingly, the type of anions plays a certain role in improving S. TFSI is the most efficient to enhance the magnitude of the S, followed by OTf and BF4. The possible rationale is because of the binary nature of both PEDOT:PSS and ILs, which consist of positively and negatively charged species. These charged species in ILs, for example, negatively charged TFSI and positively charged BMIM, will interact with correspondingly positively charged polymer PEDOT and negatively charged PSS chains via electrostatic interactions.PF of PEDOT:PSS films. The σ, S, and PF of the ILs-SFS-F-PEDOT:PSS films with different concentrations of ILs are summarized in S of ~60.8 μV/K compared to SFS-F-PEDOT:PSS (51.8 μV/K), while the σ (~631 S/cm) decreased slightly. Consequently, the PF of BMIM-TFSI-SFS-F-PEDOT:PSS reached 239 μW/K2m, about ~29% enhancement over that of F-SFS-PEDOT:PSS. Similar to the first series post-treatment, the PF was nearly independent on the IL concentration, resulting in an average PF of 235 μW/K2m for BMIM-TFSI-SFS-F-PEDOT:PSS films. These values are among the highest PFs reported in the literature  to verify that the observed changes are not related to interactions of the solvent with the PEDOT:PSS film. MeOH-F-PEDOT:PSS and MeOH-SFS-F-PEDOT:PSS control films showed PFs of 92.5 and 189 μW/K2m, respectively. These values are smaller than those of the IL-F-PEDOT:PSS and IL-SFS-F-PEDOT:PSS films. Therefore, ILs in methanol has a more significant influence on the S and σ of PEDOT:PSS films than pure methanol.In the second series post-treatment, SFS was introduced to treat PEDOT:PSS before applying ILs treatment. Based on our previous findings , subsequent treatment of F-PEDOT:PSS with SFS can reduce the doping level, and as a result, improve the terature  (Bubnovaterature . This en2p X-ray photoemission spectroscopy (XPS) was employed to study the influence of IL treatment . After binary dedoping (IL-F-PEDOT:PSS & IL-SFS-F-PEDOT:PSS), the oxidation level changes and the main peaks shifted to 900 nm for polaron (PEDOT+) and to 600 nm for neutral (PEDOT) redox states  is obtained from the energy gap between the inelastic secondary electron emission cutoff and the Fermi edge and hv is the photon energy of the UPS light source . Ultraviolet photoelectron spectroscopy (UPS) is a key technique to determine the Φ of surfaces by measuring the secondary-electron cut-off (Ec). The influence of the Φ and the valence band on the pristine and treated PEDOT:PSS films was determined using UPS measurements . The Φ cS gives the energetic difference between the transport level (Eμ) and the Fermi level (EF) by its value and the transport type (p or n by its sign). The theoretical result indicates, the S generally depends on the Fermi level as expressed  is the differential conductivity at energy E, EF is the Fermi level, and e is the electronic charge. The integrations extend over the entire energy range. This derivation holds for both delocalized and localized states, i.e., band and hopping transport, only the assumption of a Fermi system is necessary. With a further assumption of unipolar charge carrier transport at one narrow transport level (Eμ) Equation (1) provides:where δσEF(T) – Eμ is interrelated to the carrier concentration n(T)  – Eμ, and thus enhance the S according to Equation (2). A similar tendency was observed in doped organic semiconductors between the n and TE properties including the σ and S . They can be assigned to the lamella stacking distance d (100) of the two distinct alternate ordering of PEDOT and the PSS chain. BMIM-TFSI-SFS-F-PEDOT:PSS films showed a slight change from 12.8 to 13.8 Å in the lamella stacking distance of the alternate ordering of PEDOT and the PSS chain (2θ of 6.7° in comparison with the XRD patterns of the pristine PEDOT:PSS. This corresponded separately to the lamella stacking distance d (100) of two distinct alternate orderings of the PEDOT and the PSS chains, suggesting a higher crystallization degree of the PEDOT:PSS film. Besides, for BMIM-TFSI-SFS-F-PEDOT:PSS film, the 2θ is further shifted to 6.7° corresponding to a lattice d spacing of 13.8 Å, and a fair improvement in diffraction peak intensity was observed. These results demonstrate that the IL treatment makes PEDOT:PSS films to prefer a specific lamella stacking between the PEDOT chains, resulting in the improved crystallinity of the PEDOT:PSS films. The (100) diffraction peak intensity was significantly improved, attributable to the improvement of the number of ordered aggregates associated with interchain π-π stacking between the PEDOT chain and the enhancement of the crystallinity of the PEDOT:PSS film. Therefore, the XRD results displayed that compared to the pristine films, IL dedoped PEDOT:PSS films showed an enhanced interchain coupling of PEDOT:PSS with a more densely packed PEDOT and lamella stacking between two assemblies, resulting in an improved S of the films through interface scattering  was further introduced into the PEDOT:PSS films, HOCH2+ ions penetrated into the PEDOT:PSS film, the HOCH2+ ions bound to the PSS anions during the treatment. The decreased steric hindrance and dramatically reduced binding effect exerted by PSS led to the conductive PEDOT chain further to elongate and achieve an extended conformation. This extended conformation led to stronger interchain interactions, resulting in a significantly enhanced σ of PEDOT:PSS that facilitates charge transport among the polymer chains (Xia and Ouyang, Based on our various observations, we suggest a model for the mechanism of TE properties enhancement for ILs-SFS-F-PEDOT:PSS films . Figure 2m, corresponding to post-treatment with formamide only, and post-treatment with both formamide and IL, respectively. An additional post-treatment step with SFS was introduced before applying to IL treatment, and the power factor could be further improved to more than 230 μW/K2m. A large tendency to enhance the power factor likely mainly originated from the improvement in the Seebeck coefficient S, which was increased from 14.9 to 28.5 and then 61 μV/K although the electrical conductivity σ reduced from a few thousand to in the range of 630–650 S/cm. Compared to the F-PEDOT:PSS film, the improvement in the S is because of the decrease in the carrier concentration n by roughly 70% in the case of BMIM-TFSI treated PEDOT:PSS. The enhancement in the S could also be explained by the dedoping process as evidenced by the absorption spectra in which a characteristic absorption peak at 600 nm appeared. The types of anions associated with ILs also played a role in affecting the magnitude of the power factor in an order of TFSI > OTf >BF4. On the other hand, the cross-plane κ reduced from 0.57 W/mK for the pristine film to 0.27 W/mK for BMIM-TFSI-SFS-F-PEDOT:PSS film is largely due to the removal of the PSS. Hence, under the optimum treatment condition, the estimated ZT of ~0.26 was achieved at 300 K, revealing the potential in the application for harvesting low-grade heat or waste thermal energy.In this study, two series post-treatments using ILs as one of the key steps were reported. Both series post-treatments considerably enhanced TE properties of PEDOT:PSS films. The first series post-treatment resulted in a big jump in the power factor from 63.6 to 137.8 μW/KAll datasets generated for this study are included in the article/TY, WC, and JX conceived and designed the experiments. TY and YZ performed the experiments and contributed to the film fabrication, measurement, and data analysis. AK, XW, and JS contributed to analysis tools, helped with the analysis, and discussed the data. TY wrote the paper. WC and JX helped revise the paper.The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.


The influence of hydrogen overflow was decreased and the current response was enhanced because the modified graphene extended the potential range of the electrode. The Gr/l-cysteine/gold electrode showed high electrochemical conductivity, producing a marked increase in anodic peak currents (vs. the glass carbon electrode (GCE) and boron-doped diamond (BDD) electrode). The calculated detection limits are 1.15, 0.30, and 1.42 µg/L, and the sensitivities go up to 0.18, 21.69, and 152.0 nA·mm−2·µg−1·L for, respectively, the BDD electrode, the GCE, and the Gr/l-cysteine/gold electrode. It was shown that the Gr/l-cysteine/gold-modified electrode is an effective means for obtaining highly selective and sensitive electrodes to detect trace levels of cadmium.Cadmium(II) is a common water pollutant with high toxicity. It is of significant importance for detecting aqueous contaminants accurately, as these contaminants are harmful to human health and environment. This paper describes the fabrication, characterization, and application of an environment-friendly graphene (Gr)/ Cadmium (Cd) has long been recognized as one of the most notable toxic heavy metals to ecosystems and human health ,2. It waConventional spectrometric measurements for metals include atomic absorption spectrophotometry (AAS) ,7,8, indTo address this issue, several nanoparticles have been modified on the surface of electrode based on nanotechnology, which has demonstrated exciting prospects in both chemical and optical determination of Cd(II) over the past decades. A variety of electrode surface modifications have been explored to increase sensitivity for metal detection. Sensitive, environment-friendly, and efficient determinations of heavy metal have been developed by grafting various kinds of nanomaterials onto the surface of electrodes. Platinum and gold electrodes in different forms and sizes have been widely used as backing material in electrochemical analysis due to their excellent electron transfer kinetics. However, they have been limited to detection in a positive potential range for most heavy metals due to the low hydrogen overvoltage that reduces the cathodic potential window, while the stripping peak of cadmium is comparatively negative. Platinum and gold electrodes can be combined with various nanoparticles and have a wide potential range.2-bonded carbon atoms [Carbon-based electrodes, such as the glass carbon electrode (GCE), the boron-doped diamond (BDD) electrode, and the graphene-modified electrode, have a wide working potential range to make extensive analyses, low background currents to obtain high sensitivity, and stable structures to overcome harsh chemical environments. Graphene, a new type of environmental film, has also shown high hydrogen overpotential, which can suppress the hydrogen overflow on a gold electrode. Graphene is a 2D nanomaterial of spon atoms ,17. Moreon atoms ,19. Sincon atoms  and exceon atoms ,23,24,25l-cysteine was selected as the linker between graphene and gold microelectrode as it provides fast electron transfer for electrochemical detection and amino group that can potentially join with graphene by dehydration-condensation reaction. The boron-doped diamond (BDD) electrode and the glass carbon electrode (GCE) were also examined for Cd measurements, and the results were compared with that of the Gr/l-cys/Au electrode.In this paper, graphene was modified on a gold electrode via a self-assembled method based on thiols and related molecules, which provided a way to perform Cd detection in a negative potential range . We trie2+ in 3% nitric acid) was purchased from the China National Research Centre for Certified Reference Material. Cadmium samples were carefully diluted from the stock solution with double-distilled water. Carboxyl graphene (2 mg/L) was from Nanjing XFNANO Materials Tech Co., Ltd. . Dichloroethane (EDC) and N-Hydroxysuccinimide (NHS) were purchased from Sigma-Aldrich . Sodium acetate and glacial acetic acid were obtained from Xilong Tech Co., Ltd. . Ferricyanide solution (0.5 mM) was added into 0.1 M KCl solution.The purities of all reagents were in analytical grade except those stated separately. Double distilled water (18 MΩ·cm) was used to prepare for samples. Cadmium standard stock solution  using a three-electrode system based on a microelectrode chip. For comparison, traditional electrochemical bulk electrodes were used, while the glassy carbon electrode and the boron-doped diamond electrode (3 mm in diameter) served as the working electrode, the platinum disk electrode (3 mm in diameter) served as a counter electrode, and Ag/AgCl (saturated KCl) served as the reference electrode.Field-emission scanning electron microscope  produced by Hitachi  was used to check the morphologies of the graphene.2SO4 until a stable curve was obtained. The gold microelectrode was dipped in 20 µL of 10 mM l-cysteine (C2H7NS) solution for 6 h at 4 °C. The l-cysteine-modified gold electrode was obtained after 6 h of immersion. The modified gold microelectrode was washed with deionized water and dried in air for 24 h. Then, a mixed solution of NHS and EDC was applied into the carboxyl graphene (GN–COOH) solution for 15 min at 4 °C. Three microliters of the graphene-mixed solution was dispensed on the surface of the l-cysteine-modified gold microelectrode for 12 h at 25 °C. The hydroxyl group of the GN–COOH bond with the amino group of l-cysteine on the Au microelectrode with those steps. Finally, the carboxyl graphene (GN–COOH)-modified gold microelectrode was modified with l-cysteine as shown in The ring-disk microelectrode chip contains a gold working microelectrode, a platinium counter electrode. The microelectrode was prepared by the MEMS technique. The gold-working electrode was fabricated by standard optical lithography and a lift-off process with a diameter of 3 mm. Before modification, the gold microelectrode was cleaned in 0.01 M HDifferential pulse stripping voltammetry (DPSV) was applied to detect trace levels of cadmium under an optimized condition. All solutions were stored in a 20-mL Teflon bottle. DPSV parameters were optimized such that cadmium was deposited for 360 s at −1.1 V in 0.1 M acetate buffer (pH 4.50). The DPSV of electrodeposit metal was performed in the potential range of −1.1 to 0.5 V. The samples were homogeneous medium via stirring during the deposition steps, and the magnetic stirrer turned off for 120 s to equipoise prior to the DPSV scan.l-cysteine/Au electrode are shown in l-cysteine composite is rougher and sheets of graphene are clear in the edge of electrode. There are some thin folds on the surface in the center of the electrode. The electrochemical properties of different gold electrodes were characterized by CV. l-cys/Au, Gr/l-cys/Au, and Gr/l-cys/Au electrodes in solution containing 0.5 mM Fe(CN)33− and 0.1 M KCl. Compared with the CV curve of the bare gold electrode (curve a), an obviously increased redox current was obtained by the l-cysteine-modified gold electrode (curve b). After the chemical bond between GN–COOH and l-cysteine layer, the redox current of Gr/l-cysteine/Au electrode (curve c) decreases compared with the l-cysteine/Au electrode. It can be seen from the reduced redox current that electron transfer was inhibited by the graphene layer. Reduction of GN–COOH to rGN–COOH (curve d) increases the conductivity of the catalyst. The existence of rGN–COOH results in a stronger combination of cadmium with the modified electrode. The subsequent stripping of cadmium was therefore kinetically harder, and the stripping potential became more negative. However, this potential shift brings about fierce hydrogen evolution, which may damage the deposition layer. Consequently, the rG/l-cys/Au electrode cannot be applied to Cd detection.The typical SEM images of Gr/l-cys/Au on the surface is shown in 2 to H2O2 at the gold surface depending on the pH of the medium, which easily occurred in acidic media [l-cys/Au electrode. Such behavior was due to the fabrication of graphene on the gold electrode and the graphene-modified gold electrode can be used in cadmium determination.The influence of oxygen on the voltammetric behaviors of the bare gold electrode and the Gr/ic media . It can l-cys/Au electrode. As the pre-concentration time increased from 120 to 840 s, the peak currents for Cd2+ at pH 4.50 linearly increased, owing to the increased amount of cadmium ion on the Gr/l-cys/Au electrode. However, the stripping currents tended to slightly deviate from the linear region after 360 s, as shown in In order to investigate the influence of the deposition time and pH value of the detection solution, experiments were designed with 10 µg/L Cd(II) by DPSV to identify the current response on the Gr/l-cys/Au (B) electrodes drawn by AFM. The height profile of one layer’s is about 120 nm along the line across the membrane surface. It is believed that 2D graphene sheets combined to create an interconnected framework. The overlap of graphene can greatly enhance the specific surface area of the Gr/l-cys/Au electrode and can give the unfolded graphene a significant character to capture metal ions during deposition time in aqueous phase [The thickness of the one layer was measured by atomic force microscope (AFM). us phase .l-cysteine composite-modified electrodes generated improved the electrochemical character in a solution containing 0.5 mM ferri/ferrocyanide and 0.1 M KCl. The redox current decreased when the amount of GN–COOH loading increased from 3 to 9 µL, indicating that adding more GN–COOH to the electrode surface could diminish the electrochemical sensitivity of modified gold electrode. Graphene incorporation into l-cysteine is crucial for improving the electrochemical properties of the composite. One graphene layer displayed the best sensitivity, stability, and firm combination.l-cysteine was used to connect the electrode surface with the graphene by a self-assembly process. Calibration samples of deionized water (DW) were used to test the analytical performance of our method. Samples were spiked with 0, 5, 10, 15, and 20 µg/L cadmium(II) from standard stock solutions. The resulting calibration plots are linear over a range from 5 to 20 µg/L, with correlation coefficients exceeding 0.95 (To detect trace levels of Cd(II), DPSV is used because of its high sensitivity and linearity . To incring 0.95 . The anal-cysteine nanocomposite-modified gold electrode was compared to the GCE and the BDD electrode in similar systems for measuring trace levels of Cd(II). l-cys/Au electrode, the glass carbon electrode, and the boron-doped diamond electrode. The sensitivities go up to 0.18, 21.69, and 152.0 nA·mm−2·μg−1·L for, respectively, the BDD electrode, the GCE, and the Gr/l-cys/Au electrode. The sensitivity of the Gr/l-cys/Au electrode was higher than the other carbon-based electrodes, and the detection limit of the proposed method was comparable to other electrochemical detection methods. It was thus shown that the Gr/l-cys/Au-modified electrode is an effective method for obtaining highly selective and sensitive electrodes for detecting trace levels of cadmium.Furthermore, carbon-based electrodes have obtained significant attention in previous reports because of its environmental-friendly effect and high sensitivity, especially the GCE, the BDD electrode, and the graphene ,32. A val-cysteine film was successfully modified on gold microelectrode, and the structure of the microelectrode chip demonstrated the fabrication of this composite electrode. The Gr/l-cysteine/gold electrode showed microelectrode behavior and yielded a high, steady current. The electrochemical characteristics of the microelectrode during modifications were investigated by cyclic voltammetry in [l-cysteine gold microelectrode, the GCE, and BDD electrode for Cd(II) determination are linear with a range from 5 to 20 µg/L, with correlation coefficients exceeding 0.95. The Gr/l-cysteine gold microelectrode showed the highest sensitivity compared with the bare glassy carbon and boron-doped diamond due to the use of graphene and microelectrodes. In addition to the present work, this modified microelectrode can also be used for the detection of other trace metals that have lower deposition potentials than cadmium.In this work, the gold disk microelectrodes with the sensing diameter of 3 mm were fabricated by the MEMS technique on a glass wafer. The novel Gr/metry in . The rep


A series of new flame retardants (FR) based on dibenzodioxaphosphepine 6-oxide (BPPO) incorporating acrylates and benzoquinone were developed previously. In this study, we examine the fire behavior of the new flame retardants in polyisocyanurate (PIR) foams. The foam characteristics, thermal decomposition, and fire behavior are investigated. The fire properties of the foams containing BPPO-based derivatives were found to depend on the chemical structure of the substituents. We also compare our results to state-of-the-art non-halogenated FR such as triphenylphosphate and chemically similar phosphinate, i.e. 9,10-dihydro-9-oxa-10- phosphaphenanthrene-10-oxide (DOPO), based derivatives to discuss the role of the phosphorus oxidation state. Polyurethanes that are synthesized by polyaddition of polyisocyanates and polyols to generate a class of materials with an extremely adaptable property profiles . The molFor PIR, additive tris(2-chloro isopropyl)phosphate (TCPP) is the state-of-the-art flame retardant (FR) ,9. It coIsobutyl bis(hydroxymethyl) phosphine oxide with an oxidation state of P of –I is an example of an FR agent with high gas phase activity . PhosphiHere, we explore the efficiency of dibenzo dioxaphosphepine 6-oxide (BPPO) compounds as FR in PIR foams. The BPPO compounds are phosphonates with an oxidation state of +III and are compared to the DOPO compounds with an oxidation state of +I. Triphenyl phosphate (TPP), a state-of-the-art non halogenated FR with an oxidation state of +V, served as benchmark. The structural motives are presented in The synthesis of the novel BPPO compounds that are listed in The addition of BPPO to unsaturated compounds via a Phospha-Michael addition ,34 more Pentane ; triphenyl phosphate , triethyl phosphate ; PEG 400 , nOH = 280 mg KOH/g; potassium acetate ; diethylene glycol ; phthalate/DEG polyester polyol PEP50AD , nOH = 240 mg KOH/g; polymeric isocyanate DESMODUR 44V70L, NCO% = 30.9 ; Emulsogen TS100 , polyether modified polysiloxane TEGOSTAB B 8421, nOH = 57 mg KOH/g ; p-tolyl isocyanate , 1,4-dioxane  were used as received. For PIR foam preparation, a solution of 25 wt% potassium acetate in DEG (nOH: 793 mg KOH/g) was used as a catalyst. The synthesis of the BPPO-containing FRs according to The preparation of the PIR foams was performed in two steps. First, a mechanical stirrer mixed the polyester polyol, stabilizers, surfactants, catalyst, blowing agent, and FR at 2000 rpm. Subsequently, the required amount of isocyanate was added. After mixing for a few seconds, the mixture was poured into an open mold to prepare the foam. During the foaming process, three distinct times  were noted all starting from the mixing of polyol formulation and isocyanate. Cream time is defined as the point at which the mixture turns creamy and starts to expand. The setting time, which is also called gel time or fiber time, reflects the time when solid fibers can be drawn from the expanding foam. The rise time indicates when the foam expansion is completed. After the foam expanded, it was removed from the mold and kept at room temperature for 24 h before the specimens were cut with a band-saw. The density, pore sizes, and cell integrity of the foams were characterized. The samples used for cone calorimetry (10 cm × 10 cm × 5 cm) were employed to calculate the density and their volume and weight was determined. Pore sizes were determined from light microscopic images. The microscope used was an Axio Imager (ZEISS) that was equipped with Axiocam 305 color camera .wm − dm) was determined . With the density of water (1 g·cm−3), the mass difference was divided by the sample volume (a3) and normalized to 100%. With the following Equation (1), the water absorption VWA (volume of absorbed water over foam volume) was obtained.The scanning electron microscopy (SEM) images were taken by a Gemini Ultra plus SEM . The water absorption was determined as a parameter for the cell integrity. Foam cubes of 4 cm × 4 cm × 4 cm were completely immersed in boiling water for 90 min. The mass difference . The foams were tested according to ISO 604 while using a 100 kN force sensor. A traverse was used for the position sensor. An initial force of 2 N was applied and the test was conducted with a velocity of 500 mm·min−1 with 100 scans per measurement. A MCT  detector was used with a resolution of 4 cm−1.The infrared spectra were measured with a Vertex 80v spectrophotometer  equipped with a golden gate diamond ATR unit (SPECAC) in the wavenumber range of 4000–600 cmThe quantitative P-content was determined by Mikroanalytisches Labor Kolbe . -1) from 25 to 800 °C at a scan rate of 10 K⋅min-1 with a sample weight of 5 mg. The thermal decomposition products were analyzed with pyrolysis-GC/MS. These experiments were carried out with a GC 5890  coupled with a pyroprobe 2000  under helium atmosphere and a flow rate of 1.0 mL·min−1.The thermal behavior was assessed by thermogravimetric analysis (TGA) using a TGA Q500  in nitrogen atmosphere  test was carried out according to DIN 4102 (B2 classification). Thus, samples with dimensions of 20 cm × 10 cm × 1 cm were vertically hung in the test chamber . A burner flame was applied for 15 s on the lower edge of the specimen. The height of the flame was measured. The test was passed when the height of the flame was lower than or equal to 15 cm.−2. The distance of the burner to sample was 25 mm. Aluminum foil was wrapped around the sides of the probe to avoid edge burning. During the measurement, time to ignition (tig), heat release rate (HRR), peak of heat release rate (PHRR), time to PHRR (tPHRR), maximum of the average rate of heat emission (MARHE), total heat released (THR), total mass loss (TML), and effective heat of combustion  were evaluated.The prepared PIR foams were cut into specimens with dimensions of 10 cm × 10 cm × 5 cm. The samples were conditioned for 48 h at 23 °C in a climate chamber with 50% relative humidity. They were tested in a cone calorimeter after 48 h  according to ISO 5660-1:1990. The heat flux was adjusted to 50 kW·mThe foams were prepared with compositions according to In these PIR foams, the chemistry of the FR additive was varied. The foams Ref-0%P, TEP-0.3%P, TPP-0.7%P, and TPP/TEP-1.0%P were used as the control foams. The formulation of Ref-0%P was used as reference and did not contain any phosphorus. In TEP-0.3%P and in most of the other foams, TEP was added at a concentration of 0.3 wt.% phosphorus to lower the polyol viscosity and improve the mixing with the isocyanate. In general, TEP increases the activity of the acetate catalyst. Foam TPP/TEP-1.0%P with TEP and TPP with a P-content of 1 wt.% was used as the benchmark. In the following, TPP was replaced by BPPO- and DOPO-based derivatives incorporating acrylates and benzoquinone. −1 (P=O stretching) dioxaphosphepine 6-oxide (BPPO) incorporating acrylates and benzoquinone were tested in PUR/PIR foams with respect to their fire performance. All FR agents were tested at comparable P-concentrations. The majority of the novel BPPO derivatives did not alter the physical properties (density and morphology) of the PIR foams. We found differences in the FR properties  based on the substituents of the acrylate employed. At 1 wt% P, the structurally more complex tBuA-BPPO turned out to be the most effective FR additive due to lower PHRR, MARHE, TSR as well as a higher residue compared to the benchmark triphenyl phosphate (phosphorus oxidation state +V). The majority of the BPPO-acrylate and itaconate derivatives behaved similar to the the benchmark, triphenyl phosphate. The novel FR were also compared to chemically similar substances based on 9,10-dihydro-9-oxy-10-phosphaphenanthrene-10-oxide (DOPO) with phosphorus in the oxidation state –I to investigate the influence of oxidation state on gas phase and condensed phase contributions to flame retardancy in PUR/PIR foams. In forced flaming combustion experiments a significant influence of the FR on charring, TSR, and MARHE was found. An enhanced charring behavior for the P(+III) compounds compared to P(-I) could be confirmed according to statements in literature


In recent years, a variety of short stems have been introduced. To date, mid- and long-term results of calcar-guided short-stem designs have been rarely available.Two hundred and sixteen calcar-guided short stems were included in combination with a cementless cup in a prospective study. Patients were allowed full weight-bearing on the first day postoperatively. Harris hip score (HHS) as well as pain and satisfaction on visual analogue scale (VAS) were assessed during a median follow-up of 61.7 months. Standardised radiographs were analysed at predefined time points regarding radiological alterations such as bone resorption and remodelling, radiolucency, osteolysis and cortical hypertrophy using modified Gruen zones.At mid-term follow-up, no revision surgery of the stem had to be performed in the whole collective. At 5 years, HHS was 97.8 (SD 4.7), satisfaction on VAS was 9.7 (SD 0.7), rest pain on VAS was 0.1 (SD 0.5), and load pain on VAS was 0.6 (SD 1.2). Compared to the 2-year results, femoral bone resorption increased significantly at the 5-year follow-up (3.9% versus 42.3%). Rate of femoral cortical hypertrophy remained stable, occurring in a total of 9 hips (4.5%). At the 5-year follow-up, 2 stems (1.0%) showed non-progressive radiolucent lines with a maximum width of 2 mm. Signs of osteolysis were not observed. Compared to the 2-year follow-up, no further subsidence was observed.The rate of stem revision (0%) at the mid-term follow-up was remarkable and indicates the principle of using a calcar-guided short stem as being a safe procedure. However, signs of bone-remodelling, indicating some amount of stress-shielding, must be acknowledged at 5 years depending on stem alignment and type of anchorage.IV, Prospective observational studyTrial registration German Clinical Trials Register, DRKS00012634, 07/07/2017 (retrospectively registered) To date, short-stem total hip arthroplasty (THA) is an increasingly established procedure. Short stems present as a bone and soft-tissue preserving alternative to conventional stems and offer the opportunity for revision with a standard length stem if needed . StudiesA great variety of short stems have been introduced to the market in the last decade, providing distinct differences in the design regarding stem length, level of osteotomy and insertion technique. Khanuja et al. proposed four categories of short stems: femoral neck only, calcar loading, lateral flare calcar loading and shortened tapered stems . HoweverIn order to prove comparable lifetimes of new-generation short stems and conventional stems, clinical and radiological follow-up studies need to be carried out, which are not disassociated from first-time use and the learning curve that comes with a new implant and implantation concept .Early clinical results of the newest generation of neck preserving, calcar-guided short stems are encouraging –20. ReceAt present, there is no data available on the long-term outcomes of calcar-guided short stems and mid-term results of different type 2 short stems, according to Khanuja et al., have rarely been published , 27.The aim of this study was to assess clinical and radiological mid-term results of a new-generation calcar-guided short stem  in a 5-year follow-up. This report updates the previously published short-term results as part of a prospective observational cohort study .n = 177 Fitmore, Zimmer; n = 39 RM Pressfit vitamys, Mathys Ltd. Bettlach) with a ceramic-polyethylene bearing couple. The implantations were performed at a single centre, in the years 2010 to 2012. All operations were performed through a minimally invasive, antero-lateral approach in a standardised surgical technique [n = 198) primary osteoarthrosis, 5.1% (n = 11) femoral head necrosis, 2.3% (n = 5) congenital dysplasia and 0.9% (n = 2) secondary osteoarthrosis. All patients started physiotherapy and were allowed full weight-bearing ambulation on the first day postoperatively.In the present prospective study, 216 consecutive cases in 162 patients were included. Surgery was performed in 73 women and 89 men. Median patient age was 63.5 years (range 33.4–88.0 years). In 54 patients, the treatment was bilateral simultaneously, 108 patients were operated unilaterally. In all patients the calcar-guided short stem optimys  was used  as well as rest pain and load pain on visual analogue scales (VAS) were assessed at every follow-up time point.For radiographic analysis all patients underwent standardised pre- and postoperative digital antero-posterior imaging according to Kutzner et al. . Using aThe subsidence was digitally measured in a standardised technique using a coordinate system according to Kutzner et al. . The meap value < 0.05 was considered as indication for difference. All statistical analyses were performed using SAS Enterprise Guide 7.13 .Data were described by median and range or by mean and standard deviation (SD). For the comparison of the radiological results between 2 and 5 years, the McNemer’s test was used (2-sided). A After 5 years, 8 patients with 10 hips were known to be deceased with the investigated implants in situ. One bilateral patient was lost to follow up at mid-term. Thus, of the initially included 216 cases, 204 hips in 153 patients could be analysed after 5 years. In two patients with three hips, only a clinical follow-up could be performed . Again, all of these occurred in Gruen zones 1, 2 and 7 (Table p = 0.1025). They occurred exclusively in Gruen zone 1. Signs of femoral cortical hypertrophy remained stable at mid-term follow-up compared to the short-term results with 9 cases (4.5%) (p = 1.0). Those were localised exclusively in Gruen zones 3 and 5  and is most likely related to the calcar-guided load-transfer given by the implant alignment in varus hips Fig. . In contThus, it is likely that not only the type of implant design has to be considered crucial regarding different patterns of bone remodelling, but also the stem alignment. This corresponds to previously published literature. Parchi et al., in a DXA study investigating the Metha stem, also came to the conclusion that bone remodelling is related to the surgical technique and the final implant position . BrinkmaTheoretically, the resorption of periprosthetic cancellous bone may contribute to mid-term migration, the rate of which has been linked to subsequent failure and to the process of aseptic loosening . HoweverLimitations have to be acknowledged. The radiological method used to evaluate femoral bone remodelling is rather inaccurate compared to the usage of the DXA method and does not allow quantification of bone loss. However, given the size of the cohort, DXA scans would have resulted in intense effort and costs. Future investigations will have to verify the results. Also, the method of measuring axial migration lacks accuracy; however, previously published EBRA-FCA analyses confirm the findings. Thirdly, a control group is lacking given the present study design. Future studies should focus on comparing calcar-guided short-stem THA with conventional THA.The present study, to our knowledge, is the first one to provide mid-term results for the specific design of the optimys stem.In conclusion, very good clinical outcomes resulted in high levels of patient satisfaction at mid-term follow-up. To date no stem revisions have had to be performed, resulting in a survival-rate of 100%. No further axial migration could be observed. Future investigations should evaluate whether these results can be maintained in a long-term follow-up.The intended preservation of bone stock can only be accomplished partially using this particular stem design. Depending on the stem alignment, an additional diaphyseal anchorage, besides the metaphyseal fixation, may result, potentially leading to some amount of stress-shielding and remodelling of the medial proximal femoral bone comparable to diaphyseal anchoring conventional stems. Future DXA studies are needed to confirm the present results. The clinical relevance of those measurements remains to be proven.


However, the association of the gut microbiota and immune recovery remains unclear. We performed a cross-sectional study on 30 healthy controls (HC) and 61 HIV-infected individuals, including 15 immunological ART responders (IRs), 20 immunological ART non-responders (INRs) and 26 untreated individuals (VU). IR and INR groups were classified by CD4+ T-cell counts of ≥350 cells/mm3 and <350 cells/mm3 after 2 years of ART, respectively. Each subject’s gut microbiota composition was analyzed by metagenomics sequencing. Levels of CD4+ T cells, CD8+HLA-DR+ T cells and CD8+CD38+ T cells were measured by flow cytometry. We identified more Prevotella and fewer Bacteroides in HIV-infected individuals than in HC. Patients in INR group were enriched with Faecalibacterium prausnitzii, unclassified Subdoligranulum sp. and Coprococcus comes when compared with those in IR group. F. prausnitzii and unclassified Subdoligranulum sp. were overrepresented in individuals in VU group with CD4+ T-cell counts <350 cells/mm3. Moreover, we found that the relative abundance of unclassified Subdoligranulum sp. and C. comes were positively correlated with CD8+HLA-DR+ T-cell count and CD8+HLA-DR+/CD8+ percentage. Our study has shown that gut microbiota changes were associated with CD4+ T-cell counts and immune activation in HIV-infected subjects. Interventions to reverse gut dysbiosis and inhibit immune activation could be a new strategy for improving immune reconstitution of HIV-1-infected individuals.Composition of the gut microbiota has been linked with human immunedeficiency virus (HIV)-infected patients on antiretroviral therapy (ART). Evidence suggests that ART-treated patients with poor CD4 Howeverfter ART . These irs, IRs) . Residuae (AIDS) . Monaco crobiota . Furtherepletion . The incral load .Previous studies have revealed alterations of gut microbiota following HIV infection and ART administration . Howevern = 15) or not  . A total of 26 treatment-naïve patients with chronic HIV-1 infection (VU) and 30 healthy matched controls were also enrolled. Ten healthy controls were from our cohort, the other 20 from our unpublished data with the same criteria in another cohort in Beijing . Subjects who have used antibiotics, probiotics, or prebiotics or have experienced diarrhea or digestive symptoms within the previous 1 month were excluded. In addition, the patients with active opportunistic infection and co-infection of HBV and HCV were also excluded from our cohort. The study received approval from the Ethics Committee of the Peking Union Medical College Hospital and the study was conducted in accordance with the approved guidelines . Signed informed consent was obtained from each subject prior to enrolment. The T-cell subjects were determined using a FACScanto flow cytometer (BD Immunocytometry Systems) . For example, the level of expression of CD28 varies, depending on the lineage and the activation state , and stored at −80°C until DNA extraction. Bead beating was used during DNA extraction to improve efficiency  . ImmunopSystems) . Freshlyon state . Approxificiency .Supplementary Table S2). The trimmed raw reads were assembled and integrated into 1.8 million non-redundant gene catalog. The sequence data from this study are deposited in the GenBank Sequence Read Archive with the accession number SRP111623.DNA library was constructed as per the manufacturer’s instruction . In brief, one paired-end library with insert the size of 350 bp for each sample was constructed and sequenced with 150 bp read length from each end on HiSeq 2500 Illumina sequencers. The raw sequencing data was processed using the MOCAT2  pipelineThe taxonomic assignment and abundance estimation was performed with MetaPhlAn 2.0  using deThe community types of each sample were analyzed using relative abundance of genera. The community type of each fecal metagenomic samples was analyzed with the same identification method as described in the original paper of enterotypes . Fisher’Permutational multivariate analysis of variance (PERMANOVA) was performed on the species abundance profile of all samples to assess the effect of age and subsets of T-cell on the composition of microbiota. Bray-Curtis distance and 9,999 permutations was used to obtain the permuted p-value in R .de novo assembled using SOAPdenovo v2   pipelinep-values were adjusted to control the false discovery rate with the method described previously . Compared to IRs, INRs featured significantly lower CD4+ T-cell as per inclusion criteria, longer duration of ART, and lower CD4/CD8 ratio. Although the CD4+ T-cell counts in the IR group were higher than those in the INR group before the initiation of ART (p = 0.002). The former still experienced better recovery on the absolute number increase of CD4+ T-cell count compared with the INR group (p = 0.010).This study included 61 male subjects who had sex with men (MSM) and 30 male matched healthy controls. No differences were observed between groups in terms of body mass index (BMI), and CD8Supplementary Table S3). There were no significant differences in alpha diversity between all the four groups . To identify possible differences between the bacterial components of subjects in these four group, we calculated the beta diversity of the samples using two estimators. Principal coordinate analysis (PCoA)  and non-metric multidimensional scaling analysis revealed a clear separation of healthy controls from the other groups at the genus level . This data suggested that gut microbiota dysbiosis in HIV-infected individuals might be due to HIV infection itself other than influence of antiretroviral therapy.Phylogenetic profiling identified 428 species from collected fecal samples . Those untreated patients had the highest percentage of enterotype 2 microbiota in gut compared with the others . Individuals on ART had a lower percentage of enterotype 2 compared to VU group , but it was still higher than healthy group . Relative abundances of both enterotypes were similar in IR and INR groups .Two enterotypes were identified, enterotype 1 dominated by −3 between VU group and HC group, we found four species were enriched in VU group and 24 species were abundant in HC group . Species more abundant in VU group mostly belong to the genus Bacteroides (n = 4), including Bacteroides coprophilus, Bacteroides coprocola, Bacteroides intestinalis, and Bacteroides salyersiae. We also observed increased Preovtella copri and Prevotella stercorea in VU group. Both of the two species belong to the genus Prevotella, which has been widely reported to be associated with HIV-1 infection in western countries (When comparing bacteria with relative abundance of more than 10ountries .F. prausnitzii and Haemophilus parainfluenzae was observed in IR and INR groups compared to VU group (FDR < 0.3). When comparing gut microbiota between the IR and INR groups, four species  were more abundant in the INR group . Interestingly, RAST showed F. prausnitzii, unclassified Subdoligranulum sp. and C. comes have the ability of producing butyrate.A lower abundance of F. prausnitzii, unclassified Subdoligranulum sp., and B. bacterium ph8 in IR group, and a higher abundance of C. comes in INR group. The result of PCoA analysis based on these four species of untreated patients with CD4+ T-cell counts >350 cells/mm3 was similar to that of the IR group . Furthermore, higher CD4+ T-cell counts (>350 cells/mm3) were accompanied with lower relative abundances of F. prausnitzii and unclassified Subdoligranulum sp.  but also in all HIV-1-infected patients . Therefore, the abundance of F. prausnitzii and unclassified Subdoligranulum sp. might have a close association with the CD4+ T-cell counts independent of ART.Compared with VU group, we noticed lower abundances of + T-cell (cells/mm3), memory CD4+ T-cell (cells/mm3), CD4+CD28+ T-cell (%), and CD8+CD38+ T-cell  were all relevant to the changes of gut microbiota among all the four groups . And the effects of age and CD4+ T-cell ratio were independent. When we focused on the IR and INR groups, age was no more a confounding factors in further analysis.To clarify the association between age, T-cell subsets and the composition of gut microbiota, multivariate analysis was performed by PERMANOVA. We found that age, CD4+ T-cells is a prominent feature of HIV infected individuals . It might suggest the increase of these two species are closely associated with T-cell activation. However, F. prausnitzii, unclassified Subdoligranulum sp., Bacteroidales bacterium ph8, and C. comes were not relevant to the changes of CD8+CD38+ T-cells (data not shown).The increase in the number and frequency of CD8ividuals . The actral load . To furtFigure 3 and Supplementary Table S7). Fatty acid biosynthesis related pathways increased in HIV-infected patients, but the others all decreased compared with healthy control (FDR < 0.1). Comparison of pathways between IR/INR and VU groups showed that ART treatment could reverse the increase of fatty acid biosynthesis. It is noteworthy that pathways involved in biotin and vitamin B5 biosynthesis decreased after ART treatment. Our data showed that the relative abundance of butyrate-producing bacteria was lower and the pyruvate fermentation pathway was down regulated in the IR group compared with the INR group .To investigate the functional role of gut microbiota in HIV infection, gene functions were analyzed by HUMAnN2 pipeline in our study. Pathways were mainly involved in amino acid, fatty acid, vitamin, and carbohydrates biosynthesis and fermentation . Although our study is based on Chinese population, our results still confirmed the same microbiota composition changes after HIV-1 infection previously observed in Western countries. We also confirmed that the diversity and composition of gut microbiota could not be recovered completely after effective ART which means that HIV-1 infection plays a significant role in disruption of gut homeostasis but could not restore normal gut environment of HIV-infected patients (Indeed, the microbiome involvement in the transmission and pathogenesis of HIV infection is being acknowledged with the changes of relative abundances of teroides  (Supplempatients .F. prausnitzii and Subdoligranulum sp. have a close connection with CD4+ T-cell counts. These two species may have persistent effect on the depletion of CD4+ T cells after HIV infection and may lead to immune non-respondence even after effective ART. Monaco and her colleagues (+ T-cell counts were accompanied with lower F. parusnitzii, with 200 cells/mm3 as the cut-off value of CD4+ T-cell counts. These findings might disclose that gut dysbiosis has a crucial role in CD4+ T-cell reconstitution since the beginning of HIV infection other than any antiretroviral therapy afterward. Explanations for this association needs to be elucidated in future studies.Interestingly we found is that the relative abundance of lleagues  also sho+ T-cell depletion and AIDS (Subdoligrnulum sp., C. comes and CD8+HLA-DR+ T cells, indicating changes of gut microbiota may be involved in immune activation. These two species were thought to be beneficial for human health, due to the fact that they have the ability of buryrate production (Systemic chronic immune activation is considered as the driving force of CD4and AIDS . The resand AIDS . Bacteriand AIDS . We founoduction . They miOur study has some limitations. Firstly, it is a cross-sectional study based on a small number of Chinese subjects. Secondly, though ART could not restore HIV-associated microbial dysbiosis, it remains hard to differentiate the effect of different antitroviral regimen on gut microbiome as in the literature . Moreove+ T-cell reconstruction, and further studies are needed to reveal the underlying mechanism. Modifying the composition of gut microbiota, for example decreasing butyrate-producing bacteria composition, might be new strategies to enhance immune reconstitution for HIV patients.In summary, our results indicate that HIV infection is the main influencing factor of gut microbiome composition. The enrichment of some butyrate-producing bacteria is associated with poor CD4The datasets supporting the conclusions of this article are included within the article and in additional files. R version 3.3.3 was used with packages ggplot2 version 2.2.1, ggplots version 3.0.1, grid version 3.3.3, and vegan version 2.4-3.This study was carried out in accordance with the recommendations of Declaration of Helsinki, the Ethics Committee of the Peking Union Medical College Hospital. The protocol was approved by the the Ethics Committee of the Peking Union Medical College Hospital. All subjects gave written informed consent in accordance with the Declaration of Helsinki.WL, TL, and BZ designed the project. YF, YH, NL, JL, XS, JX, ZQ, and TZ did the experiments. FL did the bioinformatics analysis. YF and FJ wrote the initial manuscript. BR and J-PR provided invaluable feedback and insights into analyses and the manuscript. All authors approved the final version of the manuscript.The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.


Therefore, adequate preoperative staging is imperative for optimal treatment planning. The aim of this study is to evaluate the impact of conventional imaging techniques, including chest X-ray and/or CT thorax-(abdomen), liver ultrasonography(US), and skeletal scintigraphy, on the distant recurrence-free interval (DRFI) in patients with IBTR, and to compare conventional imaging with This study was exclusively based on the information available at time of diagnoses of IBTR. To adjust for differences in baseline characteristics between the three imaging groups, a propensity score (PS) weighted method was used.18F-FDG PET-CT, and in 168 of the patients (33.9%) no imaging was used (N = 168). After a follow-up of approximately 5 years, 14.5% of all patients developed a distant recurrence as first event after IBTR. After adjusting for the PS weights, the Cox regression analyses showed that the different staging methods had no significant impact on the DRFI.Of the 495 patients included in the study, 229 (46.3%) were staged with conventional imaging, 89 patients (19.8%) were staged with 18F-FDG PET-CT over conventional imaging techniques.This study showed a wide variation in the use of imaging modalities for staging IBTR patients in the Netherlands. After using PS weighting, no statistically significant impact of the different imaging modalities on DRFI was shown. Based on these results, it is not possible to recommend staging for distant metastases using The online version of this article (10.1007/s10549-019-05205-z) contains supplementary material, which is available to authorized users. In patients with ipsilateral breast tumor recurrence (IBTR), adequate preoperative staging is imperative for tailoring optimal treatment plans. The absence or presence, and if so, the extensiveness of distant metastases determines the curative or palliative intent of the treatment of patients with IBTR . To eval18F-FDG PET) and 18F-FDG PET computer tomography (18F-FDG PET-CT) in patients with cancer [18F-FDG PET and CT technique provides anatomical and functional information, and has been demonstrated to be an accurate technique in staging patients with IBTR and for the detection of distant metastases [18F-FDG PET-CT [18F-FDG PET-CT is able to screen the whole body, including regional lymph nodes, in one session and may reduce the need for additional diagnostic procedures often needed to further analyze lesions found on conventional staging images [Besides these conventional imaging techniques, studies have focused on the value of 18-Flurorine-2-Fluoro-2-deoxy-D-Glucose positron emission tomography  study is a multicenter national registration study in which 36 Dutch hospitals participated , 17. Pat18F-FDG PET-CT, or no staging at all. Conventional imaging included the use of the following imaging techniques: (1) chest X-ray and/or CT thorax-(abdomen), (2) ultrasonography (US) of the liver or CT thorax-(abdomen), and (3) skeletal scintigraphy. Patients in the conventional imaging group who did not undergo a scan of the thorax, liver, and skeletal scintigraphy were excluded.All patients with IBTR, treated with a curative intent, and staged cTxN0M0 were considered eligible for inclusion. All included patients were divided into three groups according to the preoperative staging procedure: conventional imaging, Distant recurrences (DR) were defined as any evidence of disease outside the ipsilateral breast, contralateral breast, and regional lymph nodes. A regional recurrence (RR) was defined as any evidence of disease found in ipsilateral intramammary nodes, ipsi- and contralateral internal mammary nodes, ipsi- and contralateral axillary nodes, and ipsi- and contralateral infra- and supra-clavicular nodes , 19. LymIn 2017, follow-up of the 536 patients in the SNARB study was updated. General practitioners were actively contacted for additional follow-up information when hospital records showed no outpatient clinic visits for more than 1 year. Date of last follow-up was documented as last visit to the outpatient clinic, date of last visit to the general practitioner, or date of death in case the patient had deceased. Follow-up time was defined as the time between date of surgery for IBTR and date of last follow-up.Distant recurrence-free interval (DRFI) was defined as the time between date of IBTR surgery and date of diagnosis of a DR or date of last follow-up. Only distant recurrences developing as first event after IBTR were recorded as a distant event. Distant recurrences occurring after a local or regional re-recurrence following IBTR were censored.p value of < 0.05 was considered statistically significant.Only the information available at time of diagnosis of IBTR, so before systemic staging imaging, was used for the analyses. The baseline characteristics were compared between the three staging groups. Categorical variables were tested with a Chi-square statistics or Fisher exact test when necessary and continuous variables were tested with a one-way ANOVA analysis. A 2-sided The effect of the method of staging on the DRFI was analyzed with the use of propensity score (PS) adjustment. A PS was calculated for every patient, based on the possible confounders. Because the outcome of interest was divided in three staging methods groups, multinomial propensity scores were used. The propensity scores were calculated with the MNPS package, an extended version of the TWANG package, in R. To obtain the propensity score weights for multiple staging methods, a generalized boosted model (GBM) regression was used. The GBM was used with 3000 number of trees and different stopping rules were checked: the mean effect size, maximal effect size, mean Kolmogorov–Smirnov, and maximal Kolmogorov–Smirnov. For the specific research question, the average treatment estimation (ATE) comparison was used.By using the GBM model, the overlaps between the three groups were checked. In practice, overlapping meant that every patient could have received each staging modality and that no values of the covariates occurred only in one of the staging groups. Box plots were used for comparing the distribution of propensity scores and testing the overlap. Generally, standardized mean differences of less than 0.20 were considered small (which is good), 0.40 were considered moderate, and 0.60 were considered large.Next to the overlap, also the balance of the three groups was assessed. Finally, a combination of the overlap plot, the balance plots, and covariate table were used to assess whether the groups were sufficiently similar to support causal estimation of the primary research question.After the propensity score weights were calculated, the weights were used in a weighted survival analysis to calculate the effect of the staging method on the DRFI. The effect was investigated with the use of Kaplan–Meier curves and tested with a Cox regression model. When a covariate was still unbalanced after PS weighting, the covariate was included in the Cox regression model to correct for it –23.Of the 536 patients for whom follow-up data were collected, 21 (4%) were lost to follow-up due to emigration, lack of information, or withdrawal of informed consent. Of the 515 (96%) remaining patients, 20 patients were only partly screened for distant metastases and therefore excluded, resulting in a study cohort of 495 patients (92.4%).p values . In Table 18F-FDG PET-CT group, more patients were primary treated with a mastectomy, and more patients had primary positive lymph nodes. In the no-staged group, the patients had a higher mean age at time of IBTR . Those patients who received no staging were treated with adjuvant systemic therapy in only 60.7% of the cases, compared to 73.4% in patients who were staged. There was no difference in the administration of adjuvant systemic therapy between the conventional imaging staged group and 18F-FDG PET-CT, 74.2% vs 71.4%, respectively (P = 0.588).The median age at the time of IBTR was 64.0 years (range 26–93). The median time from primary surgery to diagnosis of IBTR (DFI) was 10.6 years (range 0.4–32). The majority of the patients had a primary tumor ≤ 2 cm (55.4%), a primary negative nodal status , and hormone receptor-positive, human epidermal growth receptor 2 (HER2)-negative (67.9%). The different covariates were divided per staging group are shown in Table 18F-FDG PET-CT, and 168 (33.9%) received no preoperative staging imaging (N = 168)  underwent preoperative staging with conventional imaging, 89 patients 19.8%) with 9.8% withN = 8). The other recurrences were located in the ipsilateral supraclavicular nodal area (N = 2), ipsilateral axillary (N = 1), parasternal (N = 2) or contralateral infraclavicular nodal area (N = 1), or in multiple regional nodal areas (N = 2). The 6-year regional recurrence-free interval was 96.1% (CI 94.1%–98.1%). Patients screened with conventional imaging had a 6-year RR of 96.4% vs. 96.2% and 95.3% for patients with no imaging and 18F-FDG PET-CT (p = 0.766).Regional recurrences as first event after IBTR occurred in 16 patients after a median time of 2.2 years (range 0.4–7.0). In eight patients, the regional recurrence was located in the contralateral axilla (N = 4) or after a regional re-recurrence (N = 6). Predominant metastatic sites were the bones , the lungs , the liver , the brain , or to other places . In 13 patients, distant recurrences were found in multiple organs . Distant recurrence as first event occurred after a median time of 2.7 years (range 0.04–8.7) following treatment of IBTR. The mean time of developing a distant recurrence after IBTR did not significantly differ between patients screened with 18F-FDG PET-CT, conventional imaging, or no imaging (p = 0.648).After a median follow-up period of 4.9 years (range 0.3–13.2) after IBTR, 82 (16.5%) patients had experienced a distant recurrence, and in 10 (12.2%) of these patients a distant recurrence was diagnosed after a local re-recurrence . The overlap between the groups is shown in Table p values, after adjusting the PS weights to the sample, are shown. After adjusting the PS weights, all the covariates, except for the covariate primary surgery, are no longer statistically significant and therefore balanced between the staging groups. Only the variable ‘primary surgery’ is taken as a covariate next to the PS weights in the cox regression model.In Table 18F-FDG PET-CT compared to no imaging and HR 0.96 (95% CI 0.55–1.67) for conventional imaging compared to no imaging . Propensity score analyses showed no difference in the likelihood of developing distant recurrence, according to the imaging strategy used at time of IBTR.In this nationwide cohort of 495 patients included in the SNARB study with an ipsilateral breast tumor recurrence, 46.3% were preoperatively staged with conventional imaging, 19.8% with At baseline, all the covariates differed significantly between the three staging groups, except for the median time from primary surgery to IBTR diagnosis. To correct for these baseline differences, a PS analyses was used, with the aim to reduce or even eliminate confounding. PS methods are particularly appealing when multiple covariables are studied, and the number of events is rare , 25. AftHistorically, IBTR has been considered a risk factor for distant recurrence and thus resulting in a poorer prognosis –28. Sync18F-FDG PET-CT [18F-FDG PET-CT could prevent false-negative outcomes, by detecting the smaller distant metastasis. Synchronous small metastases missed at time of IBT could continue to grow, and could become clinical overt during follow-up. Thereby, 18F-FDG PET-CT is deemed to be especially valuable in the detection of extra-axillary nodal metastases [In the current study, we did not observe a difference in the meantime to detection of distant recurrence, nor in the risk of regional recurrences after IBTR, between the different imaging strategies. Although current guidelines recommend the use of chest X-ray, liver ultrasonography or CT, and bone scintigraphy, these imaging modalities have been shown to be less sensitive and specific than G PET-CT . Theorettastases , 30. In Imperative for patients is the impact of distant staging on patients’ treatment plan. Changes in treatment plans could include initiation or avoidance of medical treatment such as hormone therapy and chemotherapy, but also surgical treatment of IBTR . If exte18F-FDG PET-CT and conventional imaging. 18F-FDG PET-CT is able to perform a whole-body evaluation in one session [18F-FDG PET-CT, whether these possible lower costs would indeed outweigh the high costs of 18F-FDG PET-CT. As was shown in this study, the percentage of patients with isolated IBTR screened with 18F-FDG PET-CT increased over the years, while the use of conventional imaging decreased. Whether 18F-FDG PET-CT should replace conventional imaging in the preoperative staging of patients with IBTR should preferably depend on more aspects besides its diagnostic accuracy and cost-effectiveness, but also on the impact on prognosis and quality of life.Over time, many studies presented the pros and cons of both  session . This wi session . However18F-FDG PET-CT, or no imaging for staging were not always reported in the patient files. All patients with IBTR and synchronous metastatic disease were not considered for inclusion and therefore not registered in the database. Data are lacking regarding the numbers of excluded patients and how these synchronous metastasis were detected. Further research is encouraged to evaluate the impact of the different imaging modalities on the prognosis and to determine factors associated with an increased risk of synchronous metastases. Lastly, the diagnostic accuracy of 18F-FDG PET-CT and conventional imaging modalities are likely to vary depending on the different techniques used between the different hospitals, regarding length of radioisotope uptake, image acquisition time, and the mode of image interpretation. Nonetheless, the current study is based on the largest cohort of patients with an IBTR, as far as we are aware of. Furthermore, this is a multicenter, nationwide study providing data of different types of hospitals in the Netherlands, representative for IBTR patients in daily practice.Some caveats apply to this study; because of its retrospective nature, reasons to use conventional imaging, 18F-FDG PET-CT over conventional imaging techniques.This study showed a wide variation in the use of imaging modalities for staging of IBTR patients in the Netherlands. After propensity score weighting, no statistically significant impact of the different imaging modalities on the DRFI was shown. Based on these results, it is not possible to recommend staging for distant metastases using Fig. 3a-b-c Balance assessment. Each panel presents balance measures for one of the staging methods. The top panel presents no staging, the middle panel presents 18F-FDG PET-CT and the bottom panel presents conventional staging Supplementary material 1 (JPG 43 KB)Supplementary material 2 (JPG 44 KB)Supplementary material 3 (JPG 45 KB)Fig. 4a-b-c Overlap assessment. Each panel presents box plots of the estimated propensity scores for oneof the staging methods. The top panel presents no staging, the middle panel presents 18F-FDG PET-CTand the bottom panel presents conventional staging Supplementary material 4 (JPG 45 KB)Supplementary material 5 (JPG 46 KB)Supplementary material 6 (JPG 36 KB)Fig. 5 Effect size plots for assessing the balance of covariables on patients. The lines in the balance plots connect the values for the same variable before and after weighting. A closed redcircle indicates a covariate for which the difference between the group means is statistically significant, and anopen red circle means no statistically significant difference. A red line identifies a variable for which thestandardized bias or effect size increases with weighting; a blue line identifies a variable for which balanceimproves with weighting.Supplementary material 7 (JPG 21 KB)Below is the link to the electronic supplementary material.


Background and purpose — Biological fixation of uncemented knee prostheses can be improved by applying hydroxyapatite coating around the porous surface via a solution deposition technique called Peri-Apatite (PA). The 2-year results of a randomized controlled trial, evaluating the effect of PA, revealed several components with continuous migration in the second postoperative year, particularly in the uncoated group. To evaluate whether absence of early stabilization is diagnostic of loosening, we now present long-term follow-up results.Patients and methods — 60 patients were randomized to PA-coated or uncoated (porous only) total knee arthroplasty of which 58 were evaluated with radiostereometric analysis (RSA) performed at baseline, at 3 months postoperatively and at 1, 2, 5, 7, and 10 years. A linear mixed-effects model was used to analyze the repeated measurements.Results — PA-coated components had a statistically significantly lower mean migration at 10 years of 0.94 mm (95% CI 0.72–1.2) compared with the uncoated group showing a mean migration of 1.72 mm (95% CI 1.4–2.1). Continuous migration in the second postoperative year was seen in 7 uncoated components and in 1 PA-coated component. All of these implants stabilized after 2 years except for 2 uncoated components.Interpretation — Peri-apatite enhances stabilization of uncemented components. The number of components that stabilized after 2 years emphasizes the importance of longer follow-up to determine full stabilization and risk of loosening in uncemented components with biphasic migration profiles. Early migration of tibial components, which can be accurately measured with radiostereometric analysis (RSA), has been shown to predict future aseptic loosening  and the Knee injury and Osteoarthritis Outcome Score (KOOS) were obtained. Both patients and observers performing clinical follow-up and RSA measurements remained blinded to the allocated group during the entire follow-up period.RSA radiographs were made on the first day after surgery when weight bearing was achieved. Subsequent examinations were performed after 3 months, 1 year, 2, 5, 7, and 10 years. RSA radiographs were performed in supine position with the knee in a calibration cage . RSA measurements were analyzed using UmRSA software . Positive directions along and about the orthogonal axes are according to RSA guidelines  and registered at ClinicalTrials.gov . Informed consent was obtained from all patients. Stryker provided funds in support of the costs associated with RSA radiographs and extra clinical follow-up examinations. The sponsor did not take any part in the design, conduct, analysis, and interpretations stated in the final manuscript.60 patients were randomized, of which 1 patient in each group was excluded on the day of surgery. Baseline characteristics were similar . During Supplementary data).PA-coated components stabilized earlier as compared with uncoated components, resulting in a lower mean migration at 10 years: 0.94 mm (CI 0.72–1.2) for the PA-coated group and 1.7 mm (CI 1.4–2.1) for the uncoated group (p < 0.001). Over time, differences in migration between groups were seen in almost any direction . Most ofSupplementary data) and 1 showed continuous migration of 0.11 mm/year up to 7-year follow-up who, despite having progressive complaints, refused to visit for 10-year follow-up . 1 uncoated component that was initially classified as loose was lost to follow-up but showed full stabilization at final (5-year) follow-up. 1 uncoated component was revised after 10 years as the patient had increasing pain and instability due to mechanical failure (see below). The PA-coated component initially classified as loose was stabilized at 5-year follow-up. None of the PA-coated components classified as stable showed continuous migration at any follow-up measurement beyond 2 years.Between 1 and 2 years of follow-up, 7 uncoated components showed more than 0.2 mm MTPM and were suspected for loosening, compared with 1 in the PA-coated group. 5 of the 7 uncoated components stabilized, while 2 did not: 1  showed continuous migration of 0.14 mm/year up to 10-year follow-up .There were no statistically significant between-group differences with respect to improvement in knee flexion, extension, both KSS scores, and 4 of 5 KOOS subscales. The KOOS subscale quality of life improved equally between groups up to 5-year follow-up (p = 1.0), but substantially decreased in the PA-coated group between 5 and 10 years, resulting in a between-group mean difference after 10-year follow-up (p = 0.02) . 1 patient (randomized to the uncoated group) received a cemented implant due to an intraoperative fissure of the proximal tibia and was excluded. 1 patient (randomized to the PA-coated group) was transferred on the day of surgery to another hospital to receive appropriate treatment after a cerebral infarct and was also excluded.  3 patients  underwent revision surgery; the first due to an early prosthetic joint infection (at 3 months), the second due to a late infection (at 1 year) and the third (at 10 years) due to mechanical failure   and continuous migration after 1 year  are associated with, and frequently used as predictors for, aseptic loosening . This patient was not flagged as “loose” through RSA measurements as MTPM values were stable up to 5 years of follow-up but further follow-up measurements were unreliable due to high condition numbers , the statistical difference in quality of life is most likely a spurious finding and not related to the implant type. Nevertheless, we continue to monitor these patients to observe whether any adverse effect of the given treatment occurs.Several limitations can be noted. First, a high number of patients were lost to follow-up. Consequently, only 16 patients were available for analysis in the PA-coated group at 10-year follow-up. However, results from the linear mixed-effects model are based on all measurements, not only on remaining patients at final follow-up. Furthermore, as most implants of the lost patients appeared to have stabilized, it is unlikely that the observed results would substantially differ from those presented if patients had continued follow-up. Results of the secondary clinical outcomes should, however, be regarded as exploratory due to the limited sample size and the lower accuracy and precision of these outcome measurements. Second, it remains unknown why 6 components stabilized while 2 did not. Logically, the magnitude of component migration plays a role in preventing the onset of a prosthesis-settling phase. However, other (baseline) factors that may predict high risk patients cannot be found without performing “one-variable-at-a-time” subgroup analyses, which are likely both underpowered and produce false-positive results due to multiple comparisons (Kent et al. In summary, the typical biphasic migration pattern of uncemented implants was seen in both the uncoated group and the PA-coated group, but the latter showed statistically significantly less mean migration and absence of components with continuous migration at 10-year follow-up. When evaluating uncemented prostheses, especially those without biological mediators to enhance bone ingrowth, the initial migration phase is longer than in cemented components and can last over 2 years. With such prostheses, short-term RSA cut-off values to determine the risk of failure seem of limited value. Evaluation should thus be based on longer follow-up data and include mean migration results as well as individual component migration results. http://dx.doi.org/10.1080/17453674.2018.1469223Tables 3 and 4 and Figures 3–5 are available in the online version of this article, The study was designed by STL. Surgeries were performed by STL and 2 other colleagues. Data collection and RSA analysis were performed by KH. Statistical analysis was done by KH and PM. KH, PM, RN, and STL interpreted the data and wrote the initial draft manuscript. KH, PM, RN, and STL critically revised and approved the manuscript.Acta thanks Anders Henricson and Leif Ryd for help with peer review of this study.